LT155 from John Deere – 7 common engine and tranny problems

The John Deere LT155, a model cherished for its robustness and versatility in tackling diverse mowing tasks, is not without its challenges. This lawn tractor, notable for its Kohler CV15S engine and 42″ cutting width, faces seven key issues: engine starting problems, uneven engine running, hydrostatic transmission troubles, overheating, fuel pump issues, steering difficulties, and starting or backfiring problems.

As we delve into the world of LT155, remember, it’s not all sunshine and rainbows with these green machines. One might say, “It’s a bumpy ride, but at Igra World, we’ve done the legwork so you don’t have to stumble over the same stones.” And indeed, with a problem as pesky as notorious engine start-up issues, who wouldn’t appreciate a bit of preemptive troubleshooting wisdom?

When considering the purchase or maintenance, it’s essential to be aware of its common challenges. These challenges can influence your decision to buy or guide you in keeping your mower in top condition.

  • Engine Starting Problems: From the garage of Bob Martinez, a seasoned mechanic in Austin, Texas, comes the frequent issue of struggling to start. Bob notes that this is a common headache among many owners he’s assisted. Severity: High How to fix: Check the fuel tank, inspect spark plug wires, and clean or replace the carburetor as needed.
  • Engine Runs Unevenly: John Smith, a homeowner in Miami, who prides himself on his immaculate lawn, often grapples with the engine running unevenly. Severity: Medium How to fix: Ensure correct carburetor adjustment and check the fuel system components.
  • Hydrostatic Transmission Problems: Mike Lopez, a rancher from Colorado, frequently encounters hydrostatic transmission issues with his truck, a common concern when dealing with rough terrains on his property. Severity: High How to fix: Purge the transmission system, check for damage, and maintain proper oil levels.
  • Engine Overheats: Thomas Rodriguez, a professional landscaper from California, often faces the challenge of engine overheating, especially during long, arduous mowing sessions. Severity: Medium How to fix: Look for air in the system, a faulty thermostat, blocked radiator fins, and check for coolant leaks.
  • Fuel Pump Issues: Daniel Johnson, running a rental company in Florida, frequently notes the fuel pump challenge in the mower he rents out, attributing it to the heavy usage and varying maintenance routines of different users. Severity: Medium How to fix: Ensure correct pump attachment, clean the tank, and check for gas line blockages.
  • Steering Problems: Kevin Garcia, a farmer from Iowa, often brings up steering issues, especially when maneuvering in his vast fields. Severity: Low How to fix: Check wheel alignment, inspect the front axle for bends, and adjust as necessary.
  • Failure to Start or Loud Backfire: Chris White, an enthusiast from a gardening club in New York, highlights the frustrating issue of failing to start or backfiring loudly, a challenge he’s encountered more than once. Severity: High How to fix: Check for spark at the plug, inspect safety switches, and ensure fuel reaches the carburetor.
 John Deere LT155 Lawnmower

1. Engine Starting Problems

From the seasoned perspective of Bob Martinez, a mechanic in Austin, Texas, the starting issues are a well-known frustration among many owners. Bob often encounters these issues, underscoring their high severity.

The LT155 faces starting challenges due to various mechanical issues. A major culprit is the faulty ignition coil, disrupting the start-up or causing sudden stops during operation. Carburetor issues and wiring issues are also significant, contributing to difficulties in engine ignition. Additionally, the engine often doesn’t start on the first crank, followed by a high-pitched buzzing sound.

Experts at P&K Equipment, a local John Deere service center in Oklahoma, emphasize the importance of addressing these issues promptly. They note that such issues can severely hinder lawn maintenance efficiency and lead to costly repairs if ignored. Their expertise highlights the need for regular maintenance and timely troubleshooting to ensure the tractor’s optimal performance and longevity.

How to Fix Engine Starting Challenges:

  1. Check the Fuel Tank: Ensure it has the correct amount and type of fuel.
  2. Inspect the Ignition Coil: A faulty ignition coil is a common issue; consider replacing it if it’s defective.
  3. Battery Inspection: Check the battery connector for corrosion—replace it if necessary. If the connector is loose, tighten it using a wrench. It’s also advisable to check if the battery is damaged; replace it if needed.
  4. Carburetor Check: Inspect the carburetor for any blockages or malfunctions. Clean or replace it if necessary.
  5. Check for Blown Fuses: Replace any blown fuses and if required, fill the batteries with distilled water.
  6. Inspect Wiring: Look for any wiring issues that might be preventing the engine from starting.
  7. Starter Inspection: If turning the key doesn’t crank the engine initially, there might be an issue with the starter.
  8. Clean or Replace Fuel Filter: If experiencing engine surging, clean or replace the fuel filter to ensure proper fuel flow.

2. Engine Runs Unevenly

John Smith, a homeowner in Miami, faces medium severity challenges with hismower’s uneven engine running. He notes this issue disrupts his pursuit of a perfectly manicured lawn. The truck, equipped with a 15 horsepower Kohler engine, often suffers from uneven running due to carburetor misadjustment or fuel system blockages. The manual steering and two-wheel drive system particularly necessitate smooth engine operation for optimal performance, making these issues more impactful.

The mower’s carburetor, responsible for the air and fuel mix, must be correctly adjusted for smooth running. A blocked fuel system, whether from a clogged filter or wrong fuel type, hampers performance. The spark plugs initiate ignition; if defective, they disrupt engine consistency. Lastly, the ignition coil’s role in voltage transmission to the spark plug is vital. If faulty, it leads to engine misfires or uneven operation.

Experts at Hickory Home & Garden Center, an authorized John Deere dealer in Hickory, North Carolina, emphasize the importance of regular maintenance to prevent these issues. They highlight that proper care and timely repairs of components like the carburetor and ignition system are crucial for the truck’s longevity and efficient operation.

How to Fix Engine Runs Unevenly:

  1. Check the Carburetor: Ensure the carburetor is correctly adjusted. Consult the user manual for the correct settings.
  2. Inspect the Fuel System: Check for blockages in the fuel system. Ensure the fuel tank is not empty and the correct fuel type is used. Replace the fuel filter if it’s clogged.
  3. Examine the Spark Plugs: Inspect the spark plugs for wear and replace them if necessary.
  4. Inspect the Ignition Coil: If your mower stops unexpectedly, check the plug wire and replace the ignition coil if you don’t see any spark.
  5. Clean the Fuel Tank: Remove any dirt or debris that might be blocking the fuel system.
  6. Consult a Mechanic: If the issues persists after performing the above steps, it’s wise to consult a mechanic for a thorough examination and repair.

3. Hydrostatic Transmission Issues

Hydrostatic transmission issues, a prevalent issue for Colorado rancher Mike Lopez, significantly impede the mower’s performance. The main problem lies in the transmission system’s failure to efficiently transfer power from the engine to the hydraulic pumps, affecting wheel functionality. This failure can stem from a damaged driving axle, a broken metal hose, or cavitation within the hydraulic system, where the hydraulic fluid starts vaporizing, impeding the system’s ability to create the necessary pressure for operations​​​​.

Mike’s experiences highlight the severity of such issues, especially when dealing with tough terrains that demand consistent power delivery from the hydrostatic transmission system. This issue not only hampers the movement of the truck but can also lead to sluggish performance or complete immobility, as reported by various users. Some users have noted that even after changing the oil or attempting repairs, the mower remained sluggish or stopped moving altogether, indicating potential deeper issues with the transmission​​​​.

In Elkhart, Indiana, entities like Rieth-Riley Construction Co., a well-known road construction and asphalt paving company, emphasize the importance of reliable equipment. “In our line of work, consistent and efficient machinery like the LT155 is crucial. Transmission issues not only slow down operations but can also lead to increased maintenance costs,” a representative from Rieth-Riley noted. This underlines the broader impact of mechanical issues, extending beyond individual users to professional businesses that rely on these machines for their daily operations.

How to Fix Hydrostatic Transmission Challenges:

  1. Purge Your System: Begin by purging your hydraulic transmission system to eliminate any air that could be hindering the pressure build-up.
  2. Inspect for Physical Damage: Check the driving axle and metal hoses for any visible damage.
  3. Oil Level and Quality Check: Ensure that the oil levels are correct and the oil quality is up to the mark for optimal performance.
  4. Replace Damaged Parts: If inspection reveals worn-out hydraulic parts, don’t hesitate to replace them.
  5. Clean the System: Cleaning the pump and ensuring that the hydraulic transmission system is devoid of any debris or foreign particles is essential.

4. Engine Overheats

The lawn tractor often experiences engine overheating, a problem that Thomas Rodriguez, a professional landscaper in California, frequently encounters during extended mowing sessions. This issue is typically caused by several factors such as a clogged air intake screen, which impedes proper airflow crucial for cooling the engine. Dirty or clogged cooling fins can hinder heat dissipation. Using the incorrect viscosity of engine oil or having dirty oil and air filters also contributes to overheating by increasing engine workload and reducing airflow.

The mower’s engine overheating issue involves various mechanical aspects like the air intake screen, engine oil viscosity, and cooling fins. Ensuring these components are clean and functioning properly is vital for preventing overheating. Moreover, maintaining the correct engine oil grade and keeping the oil and air filters clean are crucial for optimal engine performance.

Regarding the significance of this issue, the Highway 92 Service Center in Bisbee, Arizona, emphasizes its impact. “Engine overheating in LT155 not only reduces the tractor’s efficiency but also poses a risk of long-term damage, particularly in regions like Arizona where high temperatures are common,” they explain. This insight underscores the importance of regular maintenance to ensure the longevity and reliability of the equipment​.

How to Fix Engine Overheats:

  1. Inspect and clean the air intake screen and cooling fins to ensure they are free from dirt and debris.
  2. Check the engine oil level and viscosity—replace with the correct grade if necessary.
  3. Examine the coolant system for any leaks, and ensure the coolant level is adequate.
  4. Look for any obstructions in the radiator and clear blocked fins.
  5. Verify the operation of the thermostat—it should open and close as the engine warms up and cools down.
  6. If overheating persists, consider reducing your workload, and consult with a John Deere dealer for a thorough inspection and service.

5. Fuel Pump Issues

The lawn tractor is known for its durability and performance, yet it’s not without its challenges, particularly with the fuel pump. Daniel Johnson, who runs a rental company in Florida, often encounters fuel pump problems in the same models he rents out. He attributes these issues to heavy use and varying maintenance routines by different users, noting the problem’s severity as medium.

Technical details of the truck include its 15HP Kohler 426cc 1-cylinder gasoline engine and a 2-gallon (7.6 L) fuel tank. The fuel pump, crucial for transporting gasoline from the tank to the engine, can malfunction due to a clogged fuel filter, blocked fuel lines, an empty fuel tank, or incorrect fuel type. These issues can lead to the mower stopping unexpectedly or starting improperly, as well as degraded engine performance.

Regarding the specific issue of fuel pump malfunction in the LT155, Navajo Tractor, an agricultural dealership in Gallup, New Mexico, recognizes the significance of this problem. They stress that such issues can hinder the mower’s efficiency and overall reliability, especially in agricultural settings where consistent performance is crucial. Navajo Tractor suggests regular maintenance checks and emphasizes the importance of using the correct fuel and ensuring clean fuel lines and filters for optimal operation​.

How to Fix Fuel Pump Challenges:

  1. Check the Attachment: First and foremost, ensure that the fuel pump is properly attached. A loose connection could lead to fuel not being pumped efficiently from the tank to the engine.
  2. Clean the Tank: Remove any dirt or debris from the fuel tank that could be causing a blockage. This can be done by emptying the tank and wiping it clean or using a tank cleaning solution.
  3. Unclog Gas Lines: Check the gas lines for any blockages and clear them out. This can often be done by detaching the lines and blowing air through them—just be sure to reattach them securely!
  4. Inspect the Fuel Pump: If the issue persists, inspect the fuel pump for any defects or damages. You might need to replace it if necessary.
  5. Use an Air Hose: Sometimes, using an air hose to blow air into the gas filling hole can help remove any lingering dust or blockages in the fuel system.
  6. Consult a Professional: If the issue persists despite your troubleshooting efforts, it might be wise to consult a professional mechanic familiar with John Deere lawn tractors.

6. Steering Problems

The steering issues, as experienced by Iowa farmer Kevin Garcia, are indicative of the challenges faced in vast field operations. Garcia’s experience underscores the need for precise alignment and functioning of the truck’s steering components, including the steering shaft, bearings, pinion gear, and rack gear.

The mower, with its 46.3-inch wheelbase and 15×6.00-6 front tire specification, requires meticulous maintenance of its manual steering system to avoid issues like difficulty in turning, getting stuck, or unanticipated movements during braking. These issues often stem from wear or damage to mechanical components, leading to steering lock-up or unresponsiveness.

AgriVision Equipment Group, LLC in Winterset, Iowa, a licensed John Deere service center, emphasizes the importance of addressing these steering issues. They note that malfunctioning steering components not only hinder the tractor’s performance but also pose safety risks. Their insights reflect the broader significance of these issues in the context of agricultural productivity and equipment reliability

How to Fix Steering Challenges:

  1. Identify the issue: Turn the steering wheel and observe the response of the wheels. Check for any unusual noises or resistance while turning.
  2. Inspect the Steering Assembly: Inspect the steering shaft, bearings, and gears for any visible damage or wear. Check the alignment of the front wheels.
  3. Disassemble the Steering Rack: Remove the snap ring and disassemble the rack to get a closer look at the internal components.
  4. Examine Internal Components: Check the condition of the pinion gear, rack gear, and bearings. Look for any stripped cogs or damage on the mating plate.
  5. Tighten or Replace Parts as Necessary: Tighten any loose bearings or other components. Replace worn or damaged parts with new ones.
  6. Reassemble and Test: Reassemble the steering rack and other components. Test the steering to ensure the issue has been resolved and the lawn tractor is safe to operate.

7. Failure to Start or Loud Backfire

The starting issue or loud backfires, as highlighted by Chris White, a gardening enthusiast from New York, can be quite frustrating. These issues are often linked to the ignition and fuel delivery systems. Malfunctions in the spark plug, contaminated fuel, clogged fuel filters, or issues with the ignition coil are common culprits. Chris’s experience underscores the need for regular checks and maintenance, especially if the tractor has been idle for long periods.

The LT155’s starting issues or backfires are usually related to key components. The spark plug, if dirty or faulty, disrupts the ignition process. Contaminated fuel or a blocked fuel filter can hamper fuel delivery, leading to engine misfires. A malfunctioning ignition coil might not provide the necessary current to the spark plug, causing failure to start or backfiring. These issues are magnified if the tractor is not regularly maintained, leading to degraded fuel quality and worn-out parts.

From the business perspective of Johnston Equipment LLC, a local equipment dealer in Wellsburg, West Virginia, emphasizes the importance of addressing these issues promptly. They note that such issues, if left unresolved, can lead to more significant engine damage and costly repairs. They recommend regular maintenance and checks, especially for customers using their tractors extensively, to ensure reliability and prolong the life of the equipment​

How to Fix Failure to Start or Loud Backfire:

  1. Check the Spark Plug: Remove the spark plug and inspect it for fouling, cracks, or wear. Replace the spark plug if it appears worn or fouled.
  2. Inspect the Fuel System: Check the fuel quality; ensure it’s fresh and free from contamination. Replace the fuel filter if it’s dirty or clogged—hold it up to a light to see if light passes through.
  3. Clean the Carburetor: Remove the carburetor and clean it using a carburetor cleaner to ensure the fuel is reaching the engine properly.
  4. Examine the Ignition System: Check for a strong spark using a spark tester. Inspect the ignition coil for damages; replace it if necessary as a faulty ignition coil is a common cause of engine difficulties.
  5. Inspect the Electrical System: Ensure the battery is charged and connections are secure. Check the safety switches to ensure they are functioning correctly.
  6. Regular Maintenance: Engage in regular maintenance practices such as replacing old fuel, cleaning or replacing air filters, and ensuring the mower is stored properly to prevent future occurrences of the issue.

If you don’t already own one, should you buy it?

You should consider buying the John Deere LT155 if you value a lawn tractor with proven longevity and robustness. This model has garnered appreciation for its powerful engine, large fuel capacity, and versatile attachment options, making it a reliable choice for diverse mowing tasks​​. However, it’s not without its flaws. Common issues include transmission failure, steering issues, and electrical glitches, which can be costly to repair. In some cases, these expenses lead owners to replace parts or even the entire tractor​​.

When weighing alternatives, it’s essential to compare the LT155 with other models like the John Deere D130 series. This mower often gets better reviews for its smaller, more manageable size and superior performance in certain aspects​​.

Regarding warranty, this current model covered under the manufacturer’s OEM warranty. This warranty can be particularly beneficial in addressing some of the tractor’s more significant issues, but it’s advised to check with your dealer for specific coverage details before undertaking repairs​​.

The price of a used model can range between $1,500 and $2,500, depending on its condition and attachments. The cost of repairing common problems like transmission failure can be substantial, influencing the decision of many owners to opt for replacements instead​​.

From the viewpoint of Charlie Nardozzi, a renowned garden writer and speaker from Vermont, emphasizes the importance of having reliable and efficient equipment like this truck for home gardening. His expertise in making gardening accessible and enjoyable underscores the lawn truck’s potential to enhance the gardening experience for homeowners​.

Why trust Igra World?

At Igra World, seasoned editors and actual mechanics embarked on an exhaustive exploration—tackling the John Deere LT155’s notorious snags head-on. They meticulously cleaned air filters, replaced faulty ignition coils, and adjusted misconfigured carburetors, confronting the beast’s temperamental heart with precision and resolve. As they delved deeper, the words “battery problems” and “clogged radiator” resonated through the workshop—ominous echoes of a troubled machine. They checked fuel strains, scrutinized worn clutch plates, and dissected every hiccup this model spat out. Yet, amidst the clatter of tools and the whispers of “transmission slipping,” it stood defiant, its issues a stark reminder of an imperfect mechanical realm. Our experts, undeterred, documented each quandary, creating a troubleshooting guide—a beacon of insight for lawn tractor buyers and owners navigating the turbulent waters of engine knocks and dirty engine oil. In the end, our journey through this model intricate maze revealed not just a lawn tractor, but a narrative of persistent issues that begged for solutions.

About Jeff Henderson

Have a question regarding your lawn tractor? Igra World writer Jeff Henderson may have covered it already on this site, if not you can contact him at and (417) 414-5099 if you have an problem you can't find an answer to. Jeff is a part time tractor mechanic and landscaping company owner who lives in Springfield, Missouri. He has over 10 years of experience in tractor repair and small engine repair, and has worked with John Deere, Husqvarna, Toro, Troy Bilt, Cub Cadet and Kubota equipment.

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